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Commit b6bddec0 authored by Lukasz Majewski's avatar Lukasz Majewski Committed by Guenter Roeck
Browse files

hwmon: (pwm-fan) Add support for using PWM FAN as a cooling device 



The PWM FAN device can now be used as a thermal cooling device.

Signed-off-by: default avatarLukasz Majewski <l.majewski@samsung.com>
Acked-by: default avatarEduardo Valentin <edubezval@gmail.com>
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent 2e5219c7

drivers/hwmon/pwm-fan.c

+88 −1
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ 
#include <linux/platform_device.h>

#include <linux/pwm.h>

#include <linux/sysfs.h>

#include <linux/thermal.h>



#define MAX_PWM 255
@@ -34,6 +35,7 @@ struct pwm_fan_ctx { 
	unsigned int pwm_fan_state;

	unsigned int pwm_fan_max_state;

	unsigned int *pwm_fan_cooling_levels;

	struct thermal_cooling_device *cdev;

};



static int  __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm)
@@ -68,6 +70,17 @@ static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm) 
	return ret;

}



static void pwm_fan_update_state(struct pwm_fan_ctx *ctx, unsigned long pwm)

{

	int i;



	for (i = 0; i < ctx->pwm_fan_max_state; ++i)

		if (pwm < ctx->pwm_fan_cooling_levels[i + 1])

			break;



	ctx->pwm_fan_state = i;

}



static ssize_t set_pwm(struct device *dev, struct device_attribute *attr,

		       const char *buf, size_t count)

{
@@ -82,6 +95,7 @@ static ssize_t set_pwm(struct device *dev, struct device_attribute *attr, 
	if (ret)

		return ret;



	pwm_fan_update_state(ctx, pwm);

	return count;

}
@@ -103,6 +117,62 @@ static struct attribute *pwm_fan_attrs[] = { 


ATTRIBUTE_GROUPS(pwm_fan);



/* thermal cooling device callbacks */

static int pwm_fan_get_max_state(struct thermal_cooling_device *cdev,

				 unsigned long *state)

{

	struct pwm_fan_ctx *ctx = cdev->devdata;



	if (!ctx)

		return -EINVAL;



	*state = ctx->pwm_fan_max_state;



	return 0;

}



static int pwm_fan_get_cur_state(struct thermal_cooling_device *cdev,

				 unsigned long *state)

{

	struct pwm_fan_ctx *ctx = cdev->devdata;



	if (!ctx)

		return -EINVAL;



	*state = ctx->pwm_fan_state;



	return 0;

}



static int

pwm_fan_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state)

{

	struct pwm_fan_ctx *ctx = cdev->devdata;

	int ret;



	if (!ctx || (state > ctx->pwm_fan_max_state))

		return -EINVAL;



	if (state == ctx->pwm_fan_state)

		return 0;



	ret = __set_pwm(ctx, ctx->pwm_fan_cooling_levels[state]);

	if (ret) {

		dev_err(&cdev->device, "Cannot set pwm!\n");

		return ret;

	}



	ctx->pwm_fan_state = state;



	return ret;

}



static const struct thermal_cooling_device_ops pwm_fan_cooling_ops = {

	.get_max_state = pwm_fan_get_max_state,

	.get_cur_state = pwm_fan_get_cur_state,

	.set_cur_state = pwm_fan_set_cur_state,

};



int pwm_fan_of_get_cooling_data(struct device *dev, struct pwm_fan_ctx *ctx)

{

	struct device_node *np = dev->of_node;
@@ -145,8 +215,9 @@ int pwm_fan_of_get_cooling_data(struct device *dev, struct pwm_fan_ctx *ctx) 


static int pwm_fan_probe(struct platform_device *pdev)

{

	struct device *hwmon;

	struct thermal_cooling_device *cdev;

	struct pwm_fan_ctx *ctx;

	struct device *hwmon;

	int duty_cycle;

	int ret;
@@ -193,6 +264,21 @@ static int pwm_fan_probe(struct platform_device *pdev) 
	if (ret)

		return ret;



	ctx->pwm_fan_state = ctx->pwm_fan_max_state;

	if (IS_ENABLED(CONFIG_THERMAL)) {

		cdev = thermal_of_cooling_device_register(pdev->dev.of_node,

							  "pwm-fan", ctx,

							  &pwm_fan_cooling_ops);

		if (IS_ERR(cdev)) {

			dev_err(&pdev->dev,

				"Failed to register pwm-fan as cooling device");

			pwm_disable(ctx->pwm);

			return PTR_ERR(cdev);

		}

		ctx->cdev = cdev;

		thermal_cdev_update(cdev);

	}



	return 0;

}
@@ -200,6 +286,7 @@ static int pwm_fan_remove(struct platform_device *pdev) 
{

	struct pwm_fan_ctx *ctx = platform_get_drvdata(pdev);



	thermal_cooling_device_unregister(ctx->cdev);

	if (ctx->pwm_value)

		pwm_disable(ctx->pwm);

	return 0;